SPIR-V doesn't support true element indexing, so we probably
need to switch over to isByRef like in llvm for this to work
properly. Currently a temporary is used, which at least
seems to work.
This will help us both to make the implementation a little
more efficient by caching emission for certain types like structs,
and also allow us to attach extra information about types that we
can use while lowering without performing a search over the entire
type tree for some property.
Follow up to https://github.com/ziglang/zig/pull/17069.
This TODO being left in was a complete oversight.
Before, any 'retryable' error would hit:
error: thread 2920 panic: access of union field 'success' while field 'failure_retryable' is active
Now, it will be reported/handled properly:
C:\Users\Ryan\Programming\Zig\zig\test\standalone\windows_resources\res\zig.rc:1:1: error: FileNotFound
When the tag is not known, it's set to `.none`. In this case, the value is either an
array of bytes (for extern unions) or an integer (for packed unions).
This was previously implemented by analyzing the AIR prior to the ZIR
`make_ptr_const` instruction. This solution was highly delicate, and in
particular broke down whenever there was a second `alloc` between the
`store` and `alloc` instructions, which is especially common in
destructure statements.
Sema now uses a different strategy to detect whether a `const` is
comptime-known. When the `alloc` is created, Sema begins tracking all
pointers and stores which refer to that allocation in temporary local
state. If any store is not comptime-known or has a higher runtime index
than the allocation, the allocation is marked as being runtime-known.
When we reach the `make_ptr_const` instruction, if the allocation is not
marked as runtime-known, it must be comptime-known. Sema will use the
set of `store` instructions to re-initialize the value in comptime
memory. We optimize for the common case of a single `store` instruction
by not creating a comptime alloc in this case, instead directly plucking
the result value from the instruction.
Resolves: #16083
Previously, @memset at comptime performed N pointer stores. This is less
efficient than just storing a whole array of values at once. The
difference can be quite drastic when reinterpreting memory - a test case
which is 40s on master branch now takes under a second on a debug
compiler build.
Resolves: #17214
This reverts commit bb98ffbe7fc8d21f48286432fe685312fd9b07cc.
This caused master branch to fail the CI. We do need to figure out why
these assertions are tripping but let's do it in a branch other than
master.
